This paper focuses on block partitioning and strain calculation in the Sichuan-Yunnan region.First,the K-medoids clustering method is used to cluster the GPS horizontal velocity field in Sichuan-Yunnan.Next,the initial classification results are further clustered based on constraints from the geographical location and velocity field of GPS stations by using the improved K-medoids method.Subsequently,the F statistical test method is used to determine the boundary of each block.Finally,the strain parameters of each block are calculated using an integral rotation linear strain model and the relationship between horizontal motion,spatial distribution of strain field,and regional tectonic deformation is analyzed.The results of the velocity field clustering analysis of GPS stations in the Sichuan-Yunnan region are consistent with the results of the alternative block division methodology based on geological theory of plate division.The strain results,which are calculated using the integral rotation linear strain model,show that the Sichuan-Yunnan rhombic block has the maximum shear strain and the highestsurface strain rate gradient.In addition,this region has accumulated some elastic strain energy,an indicator of earthquake risk.